Research On Defect Bored Pile Detection Based On Optical Fiber Temperature Measurement Technology

Piles have been widely used in foundation engineering by the good adaptability,capacity,stability,etc.However,due to the impact of factors geological conditions,equipment technology and construction materials in the construction,piles could been prone to all kinds of defects and created serious impact to the construction quality and schedule.So pile testing has been an essential engineering work.For now commonly detection methods have limitations of heavy-equipment,low-efficiency,high-cost,and couldn't automatic online monitoring,optical fiber temperature measurement technology have been attention by its advantages of high-precision,resistance to interference,long-distance and long-term online monitoring.In this thesis,the pile detection method of optical fiber temperature measurement technology is proposed based on summarizing the pile defect formation and detection method.The method is studied by the analysis of basic theory,and the different defect model tests are designed.The main research results are concluded as follows:(1)The causes and hazards of defective piles have been analyzed,and put forward the necessity of pile testing.The development status of pile testing technology has been summarized.The application status of optical fiber temperature measurement technology in pile testing has been studied.The principle of bored pile foundation detection of optical fiber temperature measurement technology is introduced.(2)Model test have been designed that five different kinds of intercalated mud pile have been made and the respective clay contents are 0?33.3%?50%?66.7%?100%.The optical fiber temperature rise in the piles have been measured to analyze the rule of the temperature rise.The relationship between the heating power and the optical fiber temperature rise have been researched and a good linear relationship have been discovered.The influence of the clay content to the optical fiber temperature rise have been researched and that the temperature rise increases with the increment of clay content have been supported by the results.(3)Model test have been designed that three different kinds of segregation pile have been made and the water-cement ratio are 0.38 ? 0.48 ? 0.58.The optical fiber temperature rise in the piles have been measured to analyze the rule of the temperature rise.The relationship between the heating power and the optical fiber temperature rise have been researched and a good linear relationship have been discovered.The influence of the water-cement ratio to the optical fiber temperature rise have been researched and that the temperature rise increases with the increment of water-cement ratio have been supported by the results.The ultrasonic transmission method has been used to detection the model test,and pros and cons between the two method have been analyzed.(4)The model of broken pile with intercalated mud has been designed and the optical fiber of pile model have been heated with different power.The optical fiber temperature rise in the pile has been monitored to analyze the rule of the temperaturerise.Experiment results show that the temperature rise of intercalated mud pile is larger than normal pile and the rise is different in power.The relationship between the heating power and the optical fiber temperature rise has been researched and a good linear relationship has been discovered.The ultrasonic transmission method has been used to detection the model test.